Question

limx--->3- 5/x-3 I think it is -inf but I don't know how to prove it

Answer 1

if x<3, x-3 < 0

5/0 = ∞

but if the denominator is negative, it is -∞

Let u = x-3

Then you have the

limit (y -> 0-) 5/u

The limit is unbounded, and it is negative.